You are best to update your graphics card bios from the manufacturer and only if you experience any problems with the card.
I would not recomend flashing the bios to another variant , it could brick your card , some wont even allow you to update with a different model bios.
Only update the bios to the model of the card that you own.
ok but what about the latest 830Mhz version bios. It is not listed on the asus website but I found it on the techpowerup website. I believe that there are only 2 to 3 variants of the asus gtx 560ti (830, 900 and the 2 GB models) right. so can I update the bios with the latest one displayed on the techpowerup website.